In this study, the effect of ARB process on the microstructural evolution and precipitation characteristics of an Al–Ag-Sc alloy was explored. Four and eight cycles of the ARB process were applied on a solution treated Al–Ag-Sc alloy. As well, artificial aging heat treatment was applied on the solution treated and the severe plastically deformed specimens in the temperature range of 100 °C–500 °C. The microstructural characterization, including dislocation characteristic and grain size measurement, were performed using Electron Backscatter Diffraction (EBSD) technique. Moreover, the precipitation behavior of the various conditions was investigated by Transmission Electron Microscopy (TEM). Hardness measurements were performed on the different conditions of this research to evaluate mechanical properties variations. Results showed that applying various cycles of the ARB process leads to the development of ultra/nano grain structure. In that sense, performing eight-cycle of the ARB process transformed the low angle grain boundaries (LAGBs) of the four-cycle ARB process condition to high angle grain boundaries (HAGBs). The sub-grain boundaries developed in the low cycle ARB process were transformed into sharp HAGBs. The grain size was reduced from about 61 μm in the solution treated situation to 600 nm, and 290 nm in the two ARB processed cases. Grain size variation was lower in the low cycle of the ARB situation compared with the high cycle of the ARB case. Aging at 100 °C did not produce any meaningful changes in the microstructure. However, artificial aging at 200 °C led to the precipitation of thin plate-like precursor of Ag₂Al precipitates and a limited amount of restoration (mostly recovery). With the effect of the former being dominant, it led to hardness increment. Artificial aging above 300 °C led to the formation of coherent/spherical Al₃Sc precipitates and extended recovery. Higher temperature aging dissolved Al/Ag precipitates and caused a full restoration. Hence, it dropped the hardness value of the specimens aged at above 400 °C.

本研究探讨了 ARB 工艺对 Al-Ag-Sc 合金显微组织演变和析出特性的影响。四个和八个循环的 ARB 工艺应用于固溶处理的 Al-Ag-Sc 合金。同样，在100°C-500°C的温度范围内对固溶处理和严重塑性变形的试样进行人工时效热处理。使用电子背散射衍射 (EBSD) 技术进行微观结构表征，包括位错特征和晶粒尺寸测量。此外，通过透射电子显微镜 (TEM) 研究了各种条件下的沉淀行为。在本研究的不同条件下进行硬度测量，以评估机械性能变化。结果表明，应用各种循环的 ARB 工艺导致超/纳米晶粒结构的发展。从这个意义上说，执行 ARB 工艺的八次循环将四次循环 ARB 工艺条件的低角度晶界 (LAGB) 转变为高角度晶界 (HAGB)。在低周 ARB 过程中形成的亚晶界转变为尖锐的 HAGB。晶粒尺寸从固溶处理情况下的约 61 微米减少到 600 纳米，在两种 ARB 处理情况下减少到 290 纳米。与 ARB 情况的高循环相比，ARB 情况的低循环中的晶粒尺寸变化较小。在 100 °C 下时效不会对微观结构产生任何有意义的变化。然而，在 200 °C 下人工时效导致 Ag 的薄板状前体沉淀₂ Al 析出和有限量的恢复（主要是恢复）。前者的作用占主导地位，导致硬度增加。300 °C 以上的人工时效导致形成相干/球形 Al ₃ Sc 沉淀物并延长恢复时间。高温时效会溶解 Al/Ag 沉淀物并导致完全恢复。因此，它降低了试样在 400 °C 以上时效时的硬度值。